Not if you use my method: Compressed air Icicle gun! You can make it out of easy to gain, inconspicuous materials (like plumbing pipe), leaves no residue of a ballistics explosion, no noise, could shoot from far away (if you get the shot right) and no murder weapon.

I kind of want to make one and say its a spud gun, same principle really

but that's wrong, you ******* retard. The ice wouldn't be strong enough to pierce the flesh, let alone be enough to kill someone. And even if there WAS a way you could kill someone with ice weapons it would still leave behind a ******* puddle, which would be easy enough for anyone with a brain to figure out.